Orientador: Franco Giuseppe Dedini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-22T04:27:38Z (GMT). No. of bitstreams: 1 Eckert_JonyJavorski_M.pdf: 14458146 bytes, checksum: b2eb0f5d4618d1873858f49c66965bec (MD5) Previous issue date: 2013 / Resumo: Dinâmica veicular é o estudo das interações entre o veículo, condutor e o ambiente bem como as reações de carga, sendo esta dividida em 3 grandes áreas: dinâmica longitudinal, vertical e lateral. Existem variações entre os métodos propostos pela literatura para o cálculo da dinâmica longitudinal do veículo, sendo que o objetivo deste trabalho é, por meio de simulações, compararem os resultados obtidos pelas diversas metodologias. Por meio de um modelo gerado com auxílio do programa de análise dinâmica de multicorpos Adams®, juntamente com o Simulink Matlab®, foram implementados os métodos de cálculo propostos pela literatura de forma a simular o comportamento de um veículo em função de uma demanda de potência gerada por meio do padrão de velocidades imposto pelos ciclos das normas brasileiras NBR6601 e NBR7024. Os resultados encontrados foram comparados por meio da correlação linear entre as curvas de torque resultantes do modelo dinâmico, possibilitando uma avaliação entre os resultados encontrados pelos diferentes métodos. Também foram avaliados o consumo de combustível, a influência da variação da massa do veículo e da estratégia de condução no comportamento dinâmico do veículo, bem como modelos complementares referentes a veículos híbridos e o efeito da adição de um modelo de embreagem no conjunto simulado / Abstract: Vehicular dynamics is the study of interactions between vehicle, driver and load reactions. The vehicular dynamics is divided into three areas: longitudinal, vertical and lateral. There are variations between the methods proposed in the literature to calculate the longitudinal dynamics of the vehicle. The purpose of this study is, through simulations; compare the results obtained by different methods. By means of a model generated by Adams® (Software of Multibody Dynamics Analysis) together with Simulink Matlab® were implemented the calculation methods proposed by literature to simulate the behavior of a vehicle according to a power demand resulting from the default speeds cycles required by Brazilian Standards NBR6601 and NBR7024. The results were compared using linear correlation between the couple curves resulting from the dynamic model, allowing an evaluation of the results reported by different methods. Were also evaluated: the fuel consumption and the influence of the mass vehicle variation, the driving strategy in the vehicle dynamic behavior, some complementary models of hybrid vehicles and the effect of add a clutch model / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

In this dissertation, a group of vehicle dynamics simulation tools is developed with two primary goals: to accurately represent vehicle behavior and to provide insight that improves the understanding of vehicle performance. Three tools are developed that focus on tire modeling, vehicle modeling and lap time simulation. Tire modeling is based on Nondimensional Tire Theory, which is extended to provide a flexible model structure that allows arbitrary inputs to be included. For example, rim width is incorporated as a continuous variable in addition to vertical load, inclination angle and inflation pressure. Model order is determined statistically and only significant effects are included. The fitting process is shown to provide satisfactory fits while fit parameters clearly demonstrate characteristic behavior of the tire. To represent the behavior of a complete vehicle, a Nondimensional Tire Model is used, along with a three degree of freedom vehicle model, to create Milliken Moment Diagrams (MMD) at different speeds, longitudinal accelerations, and under various yaw rate conditions. In addition to the normal utility of MMDs for understanding vehicle performance, they are used to develop Limit Acceleration Surfaces that represent the longitudinal, lateral and yaw acceleration limits of the vehicle. Quasi-transient lap time simulation is developed that simulates the performance of a vehicle on a predetermined path based on the Limit Acceleration Surfaces described above. The method improves on the quasi-static simulation method by representing yaw dynamics and indicating the vehicle's stability and controllability over the lap. These improvements are accomplished while maintaining the simplicity and computational efficiency of the two degree of freedom method. / Graduation date: 2013

All vehicles have changing payloads that affect their dynamic response. Compared to passenger vehicles, heavy machinery have larger and more greatly varying payload masses, higher centers of mass, and encounter larger disturbances. These factors lead to significant increases in the amount of vibration experienced by heavy machinery operators. This fact, when coupled with the large amount of exposure time that a typical heavy machinery operator incurs, leads to much greater vibration dosage values for the heavy machinery operator. In addition, the heavy machinery operator faces equal or greater opportunity for accident. The chance of accident, along with the increased vibration dosage, leads to an operating condition with significant safety risks, both short and long term. It has been shown that payloads affect both the stability and vibration isolation properties of a vehicle. Large payloads reduce vehicle stability while increasing the amount of vibration transmitted to the operator. A method to compensate for these loading affects would prove to be a useful technique to increase the safety of the vehicle, both in terms of accident avoidance and long term health effects of vibration. This thesis provides such payload compensation techniques. Improved vehicle dynamics were accomplished with the use of both active and semi-active suspension control. The active systems used are optimal control based, and provided the greatest improvements in vehicle performance. An optimal controller designed around a nominal payload, however, proved insufficient for operation over the entire payload range due to too large peak actuator forces at low payloads. A multiple model approach was used to remedy this problem. Semi-active systems based on a Linear Quadratic Regulator with output feedback and damping selection via static deflection were developed. The semi-active systems would require far less power than the active systems, with the need for knowledge of fewer systems states. It was shown that despite these lower demands, the semi-active systems closely approach the performance of the fully active systems.

Orientador: Mauricio Vicente Donadon / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-19T06:12:50Z (GMT). No. of bitstreams: 1 Santos_MarcosAugustoAzevedodos_M.pdf: 10750432 bytes, checksum: 34498e6ae857842760b5a562b4e58bc8 (MD5) Previous issue date: 2011 / Resumo: Este trabalho consiste em analisar de forma dinâmica, via elementos finitos (FEA), um radiador de água utilizado em um veículo comercial pesado, com capacidade de carga acima de 22 toneladas e motorização acima de 220 cavalos vapor (cv), com foco específico no suporte lateral do radiador, responsável por fixar o conjunto de arrefecimento (radiador de água e radiador de ar) à longarina do caminhão. A análise baseia-se em dados coletados no campo de prova do cliente em questão e replicados à peça atual, a qual já passou por todos os testes de validação como bancada de vibração em três eixos ("hydro-pulse") e rodagem no campo de prova - rota de durabilidade com 35.204Km. Tendo como resultado do FEA aprovado, propor-se-á uma nova espessura de suporte de fixação, visando o limite da redução sem comprometer a vida em fadiga. Um modelamento simplificado do radiador será feito para que seja possível otimizar e reduzir o tempo de simulação, permitindo propor uma eventual mudança no conceito de análise de elementos finitos da empresa. Neste trabalho também será focado na vida em fadiga, estudando referências bibliográficas que suportarão o conceito para análise de durabilidade do componente em questão. Por se tratar de uma dissertação de Mestrado Profissional e o intuito final será replicar o conhecimento dentro da Behr Brasil, empresa que apóia este trabalho (um maior foco será dado abaixo), faremos uma correlação entre a metodologia atual utilizada na companhia e esta aqui empregada / Abstract: This job consists in analyzing dynamically, through Finite Elements (FEA), a water radiator used in heavy duty truck, with load capacity over 22 tons and engine with over 220 horse Power (HP), with a specific focus on the side bracket, which is used to fix the cooling module (water radiator and charge air cooler) into the truck chassis. The analysis is based on data gathered on customer's proving ground and replied to the current part, which has already passed through all validation tests, such as the 3 axis test bench ("hydro-pulse") and field test - durability route with 35.204Km. Having the FEA result validated a new side bracket thickness will be proposed, looking for the reduction without compromise the fatigue life expectation. A simplified model of the water radiator will be made, in order to optimize and reduce the simulation time, allowing eventually a concept change from the company's finite elements analysis methodology. In this job fatigue life expectation will be also addressed. The study will be based on references that allow the component durability analysis. For being a professional master, the expected final results consist of replying the learned knowledge inside the Behr Brasil Company (a deeper focus on the company will be given later), as well as the correlation between the current methodology used in the company and the one used in the present study / Mestrado / Dinâmica / Mestre em Engenharia Automobilistica

Two vehicular optimal control problems are visited. The first relates to the minimum lap time problem, which is of interest in racing and the second the minimum fuel problem, which is of great importance in commercial road vehicles. Historically, minimum lap time problems were considered impractical due to their slow solution times compared with the quasi-steady static (QSS) simulations. However, with increasing computational power and advancement of numerical algorithms, such problems have become an invaluable tool for the racing teams. To keep the solution times reasonable, much attention still has to be paid to the problem formulation. The suspension of a Formula One car is modelled using classical mechanics and a meta-model is proposed to enable its incorporation in the optimal control problem. The interactions between the aerodynamics and the suspension are thereby studied and various related parameters are optimised. Aerodynamics plays a crucial role in the performance of Formula One cars. The influence of a locally applied perturbation to the aerodynamic balance is investigated to determine if a compromise made in design can actually lead to lap time improvements. Various issues related to minimum lap time calculations are then discussed. With the danger of climate change and the pressing need to reduce emissions, improvements in fuel consumption are presently needed more than ever. A methodology is developed for fuel performance optimisation of a hybrid vehicle equipped with an undersized engine, battery and a flywheel. Rather than using the widely used driving cycles, a three-dimensional route is chosen and the optimal driving and power management strategy is found with respect to a time of arrival constraint. The benefits of a multi-storage configuration are thereby demonstrated. Finally, the nonlinear stability of a vehicle model described by rational vector fields is investigated using region of attraction (RoA) analysis. With the aid of sum-of-squares programming techniques, Lyapunov functions are found whose level sets act as an under-approximation to the RoA. The influence of different vehicle parameters and driving conditions on the RoA is studied.

Orientador: Milton Dias Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-17T17:39:07Z (GMT). No. of bitstreams: 1 Simionatto_ViniciusGabrielSegala_M.pdf: 5623305 bytes, checksum: 1fa9e5b17f2a168dfa754ee947f53417 (MD5) Previous issue date: 2011 / Resumo: O desenvolvimento de novas tecnologias na área automotiva e as restrições cada vez mais apertadas com relação a emissões culminaram em veículos cada vez mais leves, silenciosos e potentes. Por este motivo, os trens de potência atuais são cada vez mais susceptíveis a fenômenos de NVH. Além disso, pelo fato de os motores atuais emitirem menor nível de ruído, alguns destes fenômenos tornam-se mais perceptíveis. Neste contexto se encaixa o trabalho atual. Sabe-se que muitos problemas desta área são solucionados realizando alterações no disco de embreagem, e por isto, neste trabalho estuda-se a influência dos parâmetros de seu pré amortecedor nos fenômenos de shuffle e clunk. São feitas análises do trem de potência linearizado, por este ser um procedimento muito comum na área de desenvolvimento deste sistema. Após isso, analisa-se o mesmo sistema, através de simulações numéricas, porém considerando não linearidades no disco de embreagem e nos engrenamentos, onde foi considerado o impact damping. Identifica-se os pares engrenados que mais contribuem para o surgimento do fenômeno de clunk, e a influência dos parâmetros do pré-amortecedor sobre ambos os fenômenos / Abstract: The development of new technologies on automotive engineering and the toughening emissions laws led to the design of lighter, more silent and more powerful vehicles. For this reason, today's powertrains are more prone to NVH phenomena. Furthermore, the noticeability of those phenomena is increased since newer engines produce lower noise levels. This is the subject in which this work fits into. It is known that many of the NVH phenomena can be attenuated by performing changes on the parameters of the clutch disc, and because of it, the influence of the parameters of the clutch damper on shuffle and clonk is studied in this work. For being a widely used procedure on the development of drivelines, a inear analysis is performed on a linearized model of a powertrain. After that, using umerical integration methods, further analyses are performed on a nonlinear model of the driveline, considering that the clutch disc and the gear meshes are nonlinearities. The latter's energy loss is modeled used impact damping. The geared pairs that contribute most for the clunk phenomenon are identified, and finally the influence of the parameters of the clutch damper on both phenomena are stated / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Orientador: Milton Dias Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-17T18:54:27Z (GMT). No. of bitstreams: 1 Miyasato_HugoHeidy_M.pdf: 3357683 bytes, checksum: 9fcd8bd237500580084498c606879165 (MD5) Previous issue date: 2011 / Resumo: Fenômenos de ruído, vibração e sua severidade (NVH) são uma grande preocupação da indústria automotiva desde o século 20. A fim de atingir uma vantagem competitiva, as montadoras têm se focado na melhora do desempenho de NVH dos seus produtos para lidar com um cenário de mercado global competitivo. No intuito de verificar o comportamento do sistema durante o processo de desenvolvimento, métodos computacionais são aplicados para encontrar melhores abordagens e na previsão de problemas, economizando tempo e orçamento da empresa gastos na construção de protótipos e testes. Nesse trabalho, gear rattle, um ruído induzido por impacto cuja causa são as engrenagens sem carga da transmissão, será modelado e simulado. É diagnosticado com maior intensidade em veículos com motores diesel em marcha lenta e excitado especificamente quando uma faixa de frequências que causa grande amplitude de vibração nos elementos internos da caixa de câmbio é alcançada. Modelos lineares do trem de potência em ponto morto ou em tração serão estudados, compreendendo as suas características básicas, tais como frequências naturais e modos associados que podem ser representativos do fenômeno. Esse sistema possui elementos com fortes não-linearidades, tais como a rigidez estratificada com histerese da embreagem e a folga entre os dentes dos engrenamentos. Uma caracterização mais realista será incluída no modelo com uma rigidez variante no tempo para o engrenamento helicoidal, utilizado em todas transmissões manuais, com uma componente dissipativa adequada aos impactos. Para verificar condições de operação que podem somente ser avaliadas segundo formulação não-linear, simulações serão realizadas para verificar a eficácia de orientações de solução e propostas de modificação encontradas na literatura / Abstract: Noise, Vibration and Harshness (NVH) phenomena are a great concern of the automotive industry since the twentieth century. In order to achieve a commercial advantage, manufacturers have focused on improving the NVH performance of their products to cope with a competitive global market scenario. To verify the behavior of the system during the design process, computational methods are applied to find a better approach and foresee problems, saving company budget and time spent in prototypes and tests. In this work, gear rattle, a impact-induced noise caused by the unloaded gear teeth inside the gearbox, will be modeled and simulated. It is diagnosed with a higher intensity in diesel vehicle engines at idle speed and in a more specific way excited when a range of frequency that causes large amplitude of vibration in the internal elements of the gearbox is reached. Linear models of the powertrain operating in idle and traction will be studied, in order to understand its basic characteristics, such as natural frequencies and associated vibration modes that could be representative to this phenomena. This system has elements with strong nonlinearities such as the stratified stiffness with hysteresis of the clutch and the backlash between the gear teeth. A more realistic feature will be included in the model with a time variable stiffness for the helical gear mesh, used in all manual transmissions, with a suitable dissipative component for the impacts. To verify operational conditions which can only be evaluated with nonlinear formulation, simulations will be made to verify the effectiveness of solution guidelines and modification procedures found in literature / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Orientador: Milton Dias Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-22T19:22:01Z (GMT). No. of bitstreams: 1 RoldaoPerestrelo_LeandroTadeu_M.pdf: 15158370 bytes, checksum: 84a10bb14b3381b619db8ff9bb97be9c (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Indiana University-Purdue University Indianapolis (IUPUI) / Belt-drives are used in many applications such as industrial machines, washing ‎machines, and accessory drives for automobiles and other vehicles. Multibody dynamics/finite ‎element numerical models have become an effective way to predict the dynamic response of ‎belt-drives. In this thesis, a high fidelity numerical model was built using a multibody ‎dynamics/finite element code to simulate a belt-drive. The belt-drive transmits power from a ‎turbine of a Rankin cycle (that uses the exhaust waste heat of the internal combustion engine as ‎heat source) to the crank shaft of the engine. The code uses a time-accurate explicit numerical ‎integration technique to solve the multibody dynamics differential equations. The belt was ‎modeled using three-node beam elements to account for the belt axial and bending ‎stiffness/damping, while the pulleys, shafts and tensioner body were modeled as rigid bodies. ‎The penalty technique was used to model normal contact between the belt and the pulleys. An ‎asperity-based friction model was used to approximate Coulomb friction between the belt and ‎the pulleys. The dynamic response predicted using the model was validated by comparing it to ‎experimental results supplied by Cummins Inc. A parameter sensitivity study was performed to ‎evaluate the change in response due to change in various belt-drive parameters. A fatigue ‎model was developed to predict the belt fatigue life using output from the explicit finite ‎element code including normal and tangential forces between the belt and the pulleys and belt ‎tension. The belt fatigue life was evaluated for alternative belt-drive configurations in order to ‎find the configuration with the longest life.‎